Treatment of sugar solutions



Patented Oct S, 1 940 f I I I p j TREATMENT OF SUGAR/SOLUTIONS. I Pedro Sanchez; Habana, Cuba, and", Eugene i N.

Ehrhart, New York, N. Y'., assigno'rs' to Sucro- H Blane, Inc., New York, NY. v No Drawing. Application August 27, 1938, Serial No.- 227,209

2 I, I H 40mins. (01. 127-48) I p a 'Ihe'present invention relates'to the decoloriza} I 'he solution is allowed to stand" in the heate'd tion of sugar solutions and more particularly to .conditionuntila scum forms on the top oithe the elimination of color-from such solutions 'by solution permitting the clear liquor to be readily the use of active chlorine. separated therefrom. Due to the fact that the Heretofore, in Patent No. 1,989,156"issued on solution; has been; heated, whatever color is January 29, 1935, to one of us,'it has'beenfproformed bythe additivechlorine compound is al: posed to decolorize certain types of sugar soluready imparted to the solution. It has been found tions by; treating the sugar solution with an heretofore that this color isdifiicult of eliminaamount .ofactive chlorine, such as a soluble hytion and in accordance with the procedure of the m pochlorite, sufiicient to remove substantially all present" invention the solution that has already of the coloring matter from the solution, probeen treatedwtih hypochlorite and heated or perducing a solution suitable for use per se or as a mitted to stand until it has acquired color,is then medium from which white crystal sugar could be treated with a small additional quantity of hygrained. pochlorite and agitated. By this procedure sub- 1 In the procedure described in the above enustantially all traces of color are removed and merated patent, a sugar solution is prepared at a syrup produced that is practically colorless and room temperature, that is to say, of below about that may be used, after a check filtration, as a 30 C., and treated with suflicient hypochlorite sugar syrup or as a sugar liquor from which white and material reacting therewith to precipitate crystal sugar may be grained. I substantially all the ash-forming ingredients It will be understood that in referringto the added to the solution,agitated and passed to hypochlorite, any suitable hypochlorite may he tanks to permit defecation and color removal to employed as for instance calcium hypochlorite, occur. After about two hours a precipitate of magnesium hypochlorite, and the like although tricalcium phosphate, together with certain imfor practical operating reasons calcium hypochlopurities in the .sugar solution, rises. to the top rite will be preferred. It will be also understood. and the clear liquor separated from the scum, that the monocalcium phosphate, added to the hydrogen peroxide added thereto as a dechlorinasolution for the purpose of eliminating all ashtor and after filtration white crystal sugar boiled forming materials added thereto, may be subtherefrom. stituted by other acids or acid salts, or both, In the production of clear, sparkling and subcapable of reacting with the metallic ion of the stantially decolorized sugar solutions by the emhypochlorite to produce an insolubleprecipitate. ployment of active chlorine as the color eliminat- However, it has been found that the calcium hying agent, certain materials are produced in the pochlorite and monocalcium phosphate are sugar solution, probably additive chlorine comeminently suited for the purpose and are prepounds, which darken in color upon standing or ,ferred in practicing the invention. 35

upon application of heat to the solution. As an example, purely illustrative of the in- It'is the object of the present invention to subvention but not limitative thereof, a solution of stantially eliminate the tendency of hypochlorite raw washed sugar of 60 Brix having a color of treated sugar solutions to acquire color upon 12 units on the Home scale was treated at 30 C.

40 standing or upon heating. with 0.18% combined hypochlorite and mono- 40 It is a further object of the present invention calcium phosphatastirred for about fifteen minto produce from a sugar solution of a given color utes, permitted to standand the scum separated a resultant decolorized solution by the employfrom the solution. The color of the solution ment of substantially less active chlorine than, was 0.7 unit on the Home scale. Upon heating has been thought necessary heretofore in'practhe solution'preparatory to graining, the color 45 ticing the invention of Patent No. 1,989,156. darkened perceptibly to 2.2.

In accordance with the procedure of the pres- A portion of the same initial solution was ent invention the sugar to be decolorized, if solid, treated at room temperature with 0.13% comis dissolved in water at room temperature, that bined hypochlorite and monocalcium phosphate,

is to say, temperatures below about 35 C., and stirred for about fifteen minutes, permitted to 50 aquantity of hypochlorite and monocalcium phosstand and the scum separated'from the solution. phate added thereto suflicient in quantity to sub- The color of the treated solution was 1.1. This stantially decolorize the solution. The sugar sosolution was heated to R, an additional lution, generally one of high Brix, is agitated and 0.03% hypochlorite was added to the hot solu- 55 then heated to a temperature of about F. tion. The col of this solution a -9 of 1 color on the Horne scale. The color of the solution preparatory to graining was found to be 1.0.

From the above it will be seen that the present invention provides a method of decolorizing sugar solutions more efliciently than heretofore by employment of hypochlorite as the decolorizing agent with the production of solutions of greater stability as to color.

-What is claimed is:

1. The method of decolorizing sugar solutions with active chlorine which comprises treating the solution with a quantity of hypochlorite sufiicient to remove a substantial portion of color from the solution and a quantity of acid or acid salt sufficient to remove substantially all the ash-forming ingredients added to the solution, and thereafter heating the solution to induce color return therein, separating the insoluble material from the solution, and then treating the solution with hypochlorite sufllcient in amount to remove the color formed upon heating. 7

2. The method of decolorizing sugar solutions with active chlorine which comprises treating the solution with a quantity of hypochlorite sufiicient to remove a substantial portion of color from the solution and a quantity of a soluble material containing the phosphate radical sufiicient to remove substantially all the ash-forming ingredients added to the solution, and thereafter heating the solution to induce color return therein, separating the insoluble material from the solution, and then treating the solution with hypochlorite sufiicient in amount to remove the color formed upon heating.

3. The method of decolorizing sugar solutions with active chlorine which comprises treating the solution with a quantity of calcium hypochlorite sufficient to remove a substantial portion of color from the solution and a quantity of monocalcium phosphate suflicient to remove substantially all thecalcium ascalcium phosphate, heating the solution to a temperature sufiicient to induce color return therein, separating the calcium phosphate and any scum adhering thereto from the solution, and then eliminating color from the so separated solution by treatment with additional hypochlo- I rite.

4. The method of decolorizing sugar solutions with active chlorine which comprises treating the solution with a soluble phosphate and a quantity of hypochlorite sufficient to produce a predeterand then treating the solution with an amount of hypochlorite suflicient to produce substantially the same color obtained after the first hypochlorite treatment.

. PEDRO SANCHEZ.

EUGENE N. EHRHART. 

